1. Field of the Invention
Cataracts are one of the most common causes of curable blindness, and cataract surgery is one of the most common operations performed in ophthalmic practice. Conventional surgical techniques have been developed over many centuries and were until recently the main form of surgery of cataracts.
In U.S. Pat. No. 3,990,452, an advanced and improved machine for performing eye surgery with ultrasonic energy was disclosed. In prior U.S. Pat. Nos. 3,776,238 and 4,099,529, an instrument for ophthalmic surgery which consists of a hollow needle with an internal movable hollow cylinder, which was capable of cutting tissue by reciprocation, and wherein an opening was formed in the outer needle so that material could be engaged by the inner plunger so as to be sheared. These prior systems were two separate and distinct machines and handpieces used separately applying ultrasonic energy and mechanical chopping or shearing for performing cataract and vitreous removal respectively. The present invention provides a single handpiece which is compact and effective in which an instrument of unique and flexible design is provided that allows the surgeon to provide ophthalmic or other types of surgery with a single instrument which can simultaneously or separately allow the application of cutting with an ultrasonic needle or with chopping and can be used for doing such operations as iridectomy, lensectomy, vitrectomy and other related eye procedures such as cutting bands and membranes in the eye. Using the same principles this instrument can be used for diagnostic, and therapeutic purposes for other organs and tissues such as liver, intravertebral disc or brain, etc.
2. Description of the Prior Art
U.S. Pat. No. 3,990,452, which was issued on Nov. 9, 1976 discloses the use of ultrasonic energy to a handheld instrument utilizing needles, curvettes, gouges and knives of various sorts for the removal of cataracts by fragmentation and emulsification. This device while effective for a soft cataract and vitreous did not adequately process hard cataracts or the vitreous hemorrhage preretinal membrane and bands and abscess.
A chopper is disclosed by one of the inventors of this application in U.S. Pat. No. 4,099,529 which comprises an improvement on U.S. Pat. No. 3,776,238. Such chopper comprises a chopping device in which a nested pair of hollow tubes or needles with an opening formed in the outer tube provides vibration of the tubes relative to each other so as to cause a shearing action to take place at a small slot near the end of the outer tube thereby chopping or nibbling away the vitreous strands and tissue. This machine has been in use satisfactorily since its invention.
There are several diseases of the eye which make it necessary to sever the vitreous strands which are long chain protein molecules (collegens) and then require that the resulting debris be removed. The vitreous is not a fluid, rather a gel with a matrix of long, thin filaments. The whole vitreous is a continuous body. Aspiration of vitreous is not safe because of this and also because of an anatomical attachment of the retina. The machines which work by suction or aspiration alone, are not effective in dealing with vitreous pathology. Since these strands are extremely tough and difficult to cut, simple severance with a scalpel is not possible and resort must be made to a more sophisticated shearing action.
Several methods have been suggested for doing this and, indeed, utilized, with the most obvious being the use of micro-scissors. A rotary type cutting with infusiourial and aspirational extractions additions for removal of the chopped vitreous tissue is known. Conor O'Mally and Ralph Hainz Sr. in their U.S. Pat. No. 3,815,604 (June 1972) also show an instrument of the dual tubular, nested type typical of the genre for cutting vitreous strands and membranes, which has proved quite effective heretofor, but which are subject to the usual limitations of this entire group of tubular shearing choppers. Instead of tubular shearing choppers, a rotary mechanism can be used to cut tissue.
The presently available phacoemulsificier uses limbal approach for removal of cataracts. This method has a very high complication rate. Not only is this system incapable of handling vitreous, but also lens material that falls into the vitreous cannot be removed by this system. Similarly, the automated vitreous instruments have shortcomings. They cannot cut and remove hard lens materials.